🧪 Add unit tests for Camera2D

tests/GameUtils.Tests/Types/Camera2DTests.cs

@@ -8,6 +8,36 @@ namespace GameUtils.Tests.Types
     [TestClass]
     public class Camera2DTests
     {
+        private const float Delta = 1e-4f;
+
+        [TestMethod]
+        public void Constructor_WithViewSize_SetsDefaultProperties()
+        {
+            var viewSize = new Vector2(800, 600);
+            var camera = new Camera2D(viewSize);
+
+            Assert.AreEqual(Vector2.Zero, camera.Position);
+            Assert.AreEqual(viewSize, camera.ViewSize);
+            Assert.AreEqual(1f, camera.Zoom);
+            Assert.AreEqual(0f, camera.Rotation);
+        }
+
+        [TestMethod]
+        public void Constructor_WithFullParameters_SetsProperties()
+        {
+            var pos = new Vector2(100, 200);
+            var viewSize = new Vector2(1920, 1080);
+            var zoom = 2f;
+            var rotation = MathF.PI / 4f;
+
+            var camera = new Camera2D(pos, viewSize, zoom, rotation);
+
+            Assert.AreEqual(pos, camera.Position);
+            Assert.AreEqual(viewSize, camera.ViewSize);
+            Assert.AreEqual(zoom, camera.Zoom);
+            Assert.AreEqual(rotation, camera.Rotation);
+        }
+
         [TestMethod]
         [DataRow(0f)]
         [DataRow(-1f)]
@@ -18,7 +48,7 @@ public void Zoom_SetInvalidValue_ThrowsArgumentOutOfRangeException(float invalid
             var camera = new Camera2D(new Vector2(800, 600));
             Assert.ThrowsExactly<ArgumentOutOfRangeException>(() => camera.Zoom = invalidZoom);
         }
-
+      
         [TestMethod]
         [DataRow(0f)]
         [DataRow(-1f)]
@@ -30,6 +60,61 @@ public void Constructor_InvalidZoom_ThrowsArgumentOutOfRangeException(float inva
                 new Camera2D(Vector2.Zero, new Vector2(800, 600), invalidZoom));
         }
 
+        [TestMethod]
+        public void Zoom_ValidValue_UpdatesZoom()
+        {
+            var camera = new Camera2D(new Vector2(800, 600));
+            camera.Zoom = 2.5f;
+            Assert.AreEqual(2.5f, camera.Zoom);
+        }
+
+        [TestMethod]
+        public void WorldToScreen_IdentityCamera_TransformsCorrectly()
+        {
+            var camera = new Camera2D(Vector2.Zero, new Vector2(800, 600), 1f, 0f);
+            var world = new Vector2(0, 0);
+            var screen = camera.WorldToScreen(world);
+
+            Assert.AreEqual(400f, screen.X, Delta);
+            Assert.AreEqual(300f, screen.Y, Delta);
+        }
+
+        [TestMethod]
+        public void ScreenToWorld_IdentityCamera_TransformsCorrectly()
+        {
+            var camera = new Camera2D(Vector2.Zero, new Vector2(800, 600), 1f, 0f);
+            var screen = new Vector2(400, 300);
+            var world = camera.ScreenToWorld(screen);
+
+            Assert.AreEqual(0f, world.X, Delta);
+            Assert.AreEqual(0f, world.Y, Delta);
+        }
+
+        [TestMethod]
+        public void WorldToScreen_And_ScreenToWorld_RoundTrip()
+        {
+            var camera = new Camera2D(new Vector2(150, -50), new Vector2(1024, 768), 1.5f, MathF.PI / 6f);
+            var originalWorld = new Vector2(200, 100);
+
+            var screen = camera.WorldToScreen(originalWorld);
+            var worldRoundTrip = camera.ScreenToWorld(screen);
+
+            Assert.AreEqual(originalWorld.X, worldRoundTrip.X, Delta);
+            Assert.AreEqual(originalWorld.Y, worldRoundTrip.Y, Delta);
+        }
+
+        [TestMethod]
+        public void GetVisibleBounds_CalculatesCorrectAABB()
+        {
+            var camera = new Camera2D(new Vector2(100, 200), new Vector2(800, 600), 2f, 0f);
+            var bounds = camera.GetVisibleBounds();
+
+            Assert.AreEqual(-100f, bounds.Min.X, Delta);
+            Assert.AreEqual(50f, bounds.Min.Y, Delta);
+            Assert.AreEqual(300f, bounds.Max.X, Delta);
+            Assert.AreEqual(350f, bounds.Max.Y, Delta);
+        }
+
         [TestMethod]
         [DataRow(1f)]
         [DataRow(2.5f)]